System Overview

Brain is implemented as a layered protocol that separates capital custody, identity, authorization, execution, and payments into distinct but coordinated components. This separation enables independent validation of each function while preserving composability and interoperability with existing infrastructure.

Design Principles

• Separation of concerns — each layer validates independently, enabling modular auditing

• Standards-based — built on ERC-4337, EIP-7702, ERC-8004, ERC-8183, and x402

• Non-custodial — the backend never holds funds or private keys

• Deterministic execution — no action bypasses identity verification, policy enforcement, or payment validation

High-Level System Flow

1. User creates an account

2. User deploys one or more agents

3. User funds agents

4. Policies and budgets are attached to agents

5. Agents propose actions

6. Policy engine evaluates and signs approvals

7. If needed, payment intents are created and settled

8. Execution is routed to on-chain or off-chain systems

9. Results and receipts are recorded

10. Trust and reputation are updated on-chain

The Seven Layers

Layer	Standard	Function
Account Abstraction	ERC-4337	Programmable smart accounts, UserOperation validation
Delegated Execution	EIP-7702	EOAs adopt Brain logic without address migration
Identity & Auth	SIWX	Cryptographic sign-in for users and agents
Trust & Reputation	ERC-8004	Persistent agent identifiers and on-chain reputation
Authorization & Policy	Brain Policy Engine	Structured constraints evaluated before every action
Execution & Commerce	ERC-8183	Conditional jobs, escrow, and external integrations
Payments	x402	HTTP-native machine payments with on-chain settlement

Standards Composition

Brain does not redefine these standards — it implements and composes them into a cohesive protocol:

• ERC-4337 → programmable accounts and UserOperation-based execution

• EIP-7702 → delegated execution for EOAs

• ERC-8004 → agent identity and trust registry

• ERC-8183 → conditional commerce and job-based settlement

• ERC-7902 → wallet capability discovery

• ERC-7769 → bundler and transaction infrastructure interfaces

• x402 → machine-native HTTP payments